Anti-icing gasoline



United States Patent 3,375,092 ANTI-ICING GASOLINE William M. Sweeney,Wappingers Falls, N.Y., assignor to Texaco Inc., New York, N.Y., acorporation of Delaware No Drawing. Filed Dec. 3, 1964, Ser. No. 415,81

Claims. (Cl. 44-64) ABSTRACT OF THE DISCLOSURE This invention relates toan additive material and to a motor fuel composition containing samehaving anti-icing properties. The additive material is the reactionproduct of alkenyl succinic acid or anhydride in which the radical hasfrom 8 to 24 carbon atoms and hydrazine having 'the formula R NNR inwhich each R represents a member selected from the group consisting ofhydrogen and an alkyl radical having from 1 to 4 carbon atoms.

This invent-ion relates to a motor fuel composition for internalcombustion engines having outstanding anti-icing, anti-stallingproperties. This improvement is based on the use of an additive which isthe reaction product of an alkylene succinic acid or anhydride with ahydrazine compound having the formula:

in which R is hydrogen or an aliphatic radical having from 1 to 4 carbonatoms.

Highly volatile winter gasoline blends are known to be prone to stallingduring engine startup periods. This problem is most frequentlyencountered under atmospheric conditions of high humidity and relativelylow temperatures ranging from about 30 to 50 F. In the operation of aninternal combustion engine, a motor fuel is vaporized to a fuel-airmixture as it passes through the carburetor. This vaporization isaccompaned by a sharp drop in the temperature of the mixture. During thestarting period as a motor fuel is vaporized under cool, humidatmospheric conditions, the temperature of the fuel-air mixture drops tofreezing temperatures resulting in the formation and deposition of iceparticles on the throttle blade and walls of the carburetor. The ice inthe carburetor partially or completely blocks the air passage betweenthe carburetor throat and the throttle valve causing stalling of theengine.

Many anti-icing, anti-stalling additives or additive combinations areknown or have been proposed for use in gasoline. While :a goodly numberare reasonably effective as anti-stalling agents, and aside from thequestion of costs, their use very often gives rise to entirely new andserious problems. As a general rule, the primary factors which willprevent the use of a gasoline additive include corrosiveness to themetal in the carburetor, or in storage tanks or other metal containerswith which the fuel comes in contact or the development of insolubleprecipitates and/or emulsions in the fuel itself which cause gas linefilter plugging or plugging of the fine passages in the carburetor.

A recent development in the field of anti-stalling motor Water, it wasfound that on mixing the gasoline became turbid as a result of theformation of an emulsion. An emulsion cannot be tolerated in gasolinebecause it will carry water present in fuel storage tanks into the fuelPatented Mar. 26, 1968 system of the motor vehicle promoting corrosionand instability of the additives in the fuel in addition to promotingboth gas line fuel filter plugging as well as blockage of the fine jetsof the carburetor.

An improved motor fuel additive has now been discovered whichsubstantially improves the anti-stalling property of gasoline containingsame. Moreover, this novel gasoline is remarkably free of filterplugging and corrosion side elfects which so often prevent the use ofotherwise effective additives.

In accordance with this invention, the improved motor fuel comprisesgasoline containing from about 0.0005 to 0.5 weight percent of theproduct produced by reacting an alkenyl succinic acid or anhydridewherein the alkenyl radical has 8 to 24 carbon atoms with a hydrazinecompound having the formula:

in which R is hydrogen or an alkyl radical having from 1 to 4 carbonatoms in a mole ratio of 2:1 to 1:4 respectively.

The reaction product of the invention may be prepared by contactingsuitable quantities of the alkenyl succinic acid or anhydride and thehydrazine compound. This may be done either with or without a mutualsolvent. Moderate heat may be employed to speed up formation of thereaction product.

The alkenyl succinic acid or anhydride component employed in making thereaction product comprises those in which the alkenyl radical has from 8to about 24 carbon atoms. It is understood that mixtures of alkenylsuccinic acids or anhydrides within the noted range may also beemployed. It is preferable to employ those alkenyl succinic acids oranhydrides in which the alkenyl group has from about 8 to 16 carbonatoms with the particularly preferred material being tetrapropenylsuccinic acid. This particular compound is prepare-d by alkylatingmaleic anhydride with propylene tetramer using as is or hydrolyzing theproduct to the acid. Specific effective compounds include octenylsuccinic acid and anhydride, ,3-dimethyl hexenyl succinic acid and itsanhydride, 4-ethyl hexenyl succinic acid and its anhydride, undecenylsuccinic acid and its anhydride, hexadecenyl succinic acid, andtetradecenyl succinic acid.

The hydrazine compound used to make the reaction product has theformula:

in which each R is hydrogen or an alkyl radical having from 1 to 4carbon atoms. Thus hydrazine itself may be employed or alkyl derivativesthereof, such as the various m-ono-, di-, triand tetra-methyl, ethyl,propyl and butyl substituted hydrazines. Unsymmetrical dimethylhydrazine is particularly preferred among the alkyl substitutedhydraz-ines.

Equal mole proportions of the alkenyl succinic acid or anhydride and ofthe hydrazine compound may be employed in preparing the anti-icingreaction product of this invention. More broadly, however, the alkenylsuccinic acid or anhydride and the hydrazine compound may be reactedwithin proportions ranging from about 2:1 to 1:4, respectively. The mosteffective reaction products were those in which substantially equal moleproportions of the two components were employed.

As an example of the preparation of the additive of the invention, 56.8gm. (0.2 mole) of tetrapropenyl succinic acid in 300 ml. of benzene wasreacted with 7 gm. (0.22 mole) of hydrazine added dropwise. The mixturewas stirred for two hours and then refluxed overnight. The reactionproduct was stripped to a pot temperature of C. to affect recovery ofthe adduct.

The following data illustrate the improvements brought 3 about by theanti-stalling, anti-icing additives of the invention. In these data, theinvention is illustrated by additives prepared from reacting eithertetrapropenyl succinic acid or tetrapropenyl succinic acid anhydridewith either hydrazine or unsymmetrical dimethyl hydrazine.

The action of the anti-icing reaction product was evaluated for itsanti-stalling, anti-icing effects in a carburetor icing demonstratorapparatus consisting of a vacuum pump equipped so that cool, moisturesaturated air from an ice tower is drawn through a simple glass tubegasoline carburetor. The gasoline sample is placed in a sample bottleand is drawn into the glass carburetor through a gauge hypodermicneedle. Evaporation of the gasoline in the gas tube further cools thecold, moist air with resulting ice formation on the throttle plate. Theformation of ice on the throttle plate causes an engine to stall and ithas been found that this condition is equivalent to a pressure dropacross the throttle plate of about 0.5 inch of mercury, and the time toreach this pressure drop is recorded. The vacuum pump is adjusted togive a vacuum of 1.8 inches mercury and the test is run until either apressure of 2.3 inches mercury has been reached or it is run for 300seconds. Since with most fuels this pressure drop is reached in l to 4minutes, 300 seconds is the maximum time for a run. A recording of 300seconds indicates no stalling within the test period. Each fuel is runfour times in succession and the average is reported. If the differencebetween the runs is great, the glass tube carburetor and the testthrottle are washed with alcohol, flushed out with gasoline and the runsrepeated. An unleaded winter grade premium gasoline having a Reid vaporpressure of about 12 gives a stall in about to 70 seconds in this test.Additives which raise the stalling time to over 200 seconds are regardedas effective anti-stalling, anti-icing additives.

The base fuel employed to evaluate the effectiveness of the additivereaction product of this invention, referred to as runs A and I below,was a winter grade premium gasoline having an ASTM Research OctaneRating of about 95.0. This gasoline had a 50% ASTM distillation point of214 F. and a Reid vapor pressure of about 11.8 lbs. and was ideallysuited for testing the effectiveness of the anti-icing reaction product.The fuels in runs B through I are the additive containing fuels derivedfrom the same base fuel showing the components and the amounts em ployedin preparing the additive.

The results of the anti-icing tests are given in Table I below whereinthe anti-icing performance of the base fuel is compared to theanti-icing property of the base gasoline minus the reaction product ofthis invention. The components of the reaction product and the moleratios in which they were reacted to produce the specific productsemployed are also given. The anti-icing test runs were conducted withthe reaction product being employed at a concentration of 14.8 lbs. per1,000 barrels of gasoline. This corresponds to about 0.0055 weightpercent for the anti-icing agent.

TABLE I.-ANTI-ICLNG TEST Fuels with anti-icing Stalling time,

reaction product: seconds A. Base fuel 44 B. TPS Acid (0.2) hydrazine(0.22) 300+ C. TPS acid (0.2) hydrazine (0.11) 300+ D. TPS acid (0.2)UDMH (0.1) 300+ E. TPS acid (0.2) UDMH (0.2) 300+ F. TPS anhydride (0.2)hydrazine (0.2) 202 G. TPS anhydride (0.2) hydrazine (0.4) 300+ H. TPSanhydride (0.2) UDMH (0.2) 294 I. TPS anhydride (0.2) UDMH (0.4) 300+ J.Base fuel 42 TPS is tetrnpropenyl succinic.

Numbers in parentheses indicate moles employed in preparing theadditive.

c UDMH is unsymmetrical dimethyl hydrazine.

The foregoing data show that the additive of the i vention is anoutstanding anti-icing additive for gasoline. This additive iscompatible with the other components normally used in gasoline includingtetraalkyl lead octane improvers, metal deactivators, gum inhibitors,and the like.

Important features of the fuels containing the anti-. icing additive ofthe invention are that it forms substantially no precipitates orinsolubles or emulsions in gasoline during the normal handling andstorage periods and is substantially non-corrosive with the result thatthe gasolines of the invention are free of corrosion and fuel filterplugging problems which have both been serious drawbacks to proposedanti-icing additives.

The base fuel blends note-d above were compared as to their corrosionproperties in a rust test. Polished strips of metal, steel strip andcarburetor metal, were placed in sample bottles containing ml. of thetest fuel together with 10 ml. of distilled water. The bottles werestoppered and shaken for one minute. The percentage of rust on the metalstrips for both the portion of the metal strip immersed in the gasolineand the part immersed in the water phase was taken over the indicatedperiod of time as shown in Table II below. The additive containing fuelshad a concentration of about 18 pounds per thousand barrels of gasolinein the additive.

'Ilme, days Gasoline, Water 4 Gasoline, Water percent Rust percent Rust1 Spot. 2 Rust Nomad-Dashes indicate that no rust was present on themetal strip.

A gasoline representative of this invention was tested for its tendencyto form an emulsion and/ or a precipitate in comparison to a knownanti-icing additive. A gasoline was prepared using a base fuel similarto that employed in Table I above containing 18 pounds per thousandbarrels of the reaction product of tetrapropenyl succinic anhydride andhydrazine. This fuel was designated Blend A. A similar fuel was preparedexcept that it contained 18 pounds per thousand barrels of N-aminoethyltetrapropenyl succinamic acid. This was designated Blend B.

560 ml. of each fuel was stirred for an hour with 30 ml. of distilledwater. At the end of this time, the stirring was stopped and the samplesobserved while standing.

Blend A separated in one minute leaving a clear gasoline. Blend Bseparated in two minutes leaving a turbid gasoline. The test shows thatthe gasoline of the invention forms no emulsion in contrast to a knowngasoline blend.

The filterability of the fuel of the invention was determined in theFilter Index Test in comparison to a base fuel containing noanti-stalling additive and to a fuel containing a commercially employedanti-stalling additive. This test involves storing samples of the testfuels over 3 percent distilled water in terneplated one gallon cans.Each week before sampling for filter index test, the test gasolines werestirred in the cans for one minute and then allowed to settle for oneminute. The filter index number is the logarithm of the relative amountof time it takes for the samples to go through a standard gasolinefilter. A filter index of 2.0 means that the test fuel took 10 timeslonger to pass through the filter than the base fuel. In Table III belowA is the base fuel containing no anti-stalling additive, B is the basefuel containing 20 pounds per thousand barrels of equal amounts of thereaction product of tetrapropenyl succinic anhydride and unsymmetricaldimethyl hydrazine in 1:1 mole ratio and a light distillate minerallubricating oil having an SUS at 100 F. of 105, and C is the base fuelcontaining 20 pounds per thousand barrels of equal amounts oftetrapropenyl succinic acid and the same lubricating oil used in Babove.

TABLE III.-FILTER INDEX Times, weeks Test Fuel A 1. 0. 93 1.07 1.00 B 1.13 0. 99 1. 02 0.97 C 1.15 1.30 1.12 2.15

of a first component selected from the group consisting of 1 alkenylsuccinic acids and anhydrides in which said alkenyl radical has from 8to about 24 carbon atoms and a hydrazine compound having the formula:

in which each R represents a member selected from the group consistingof hydrogen and an alkyl radical having from 1 to 4 carbon atoms,prepared by reacting said first component with said hydrazine compoundat a mole ratio in the range of 2:1 to 1:4 respectively.

2. A gasoline additive according to claim 1 in which said reaction isconducted at mole ratios in the range of 1:1 to 1:2 respectively.

3. A gasoline additive according to claim 1 in which said alkenylradical has from 10 to 16 carbon atoms.

4. A gasoline additive according to claim 1 prepared by reactingtetrapropenyl succinic acid with hydrazine.

5. A gasoline having improved anti-stalling, anti-icing propertiescontaining from about 0.0005 to 0.05 weight percent of the reactionproduct of a first component selected from the group consisting ofalkenyl succinic acids and anhydrides in which said alkenyl radical hasfrom 8 to about 24 carbon atoms and a hydrazine compound having theformula:

in which each R represents a member selected from the group consistingof hydrogen and an alkyl radical having from 1 to 4 carbon atoms,prepared by reacting said first component with said hydrazine compoundat a mole ratio in the range of 2:1 to 1:4 respectively.

6. A gasoline composition according to claim 5 in which said reactionproduct is prepared by reacting said components at a mole ratio in therange of 1:1 to 1:2 respectively.

7. A gasoline composition according to claim 5 in which said alkenylradical has from 10 to 16 carbon atoms.

8. A gasoline composition according to claim 5 in which said reactionproduct is prepared by reacting tetrapropenyl succinic acid withhydrazine.

9. A gasoline composition according to claim 5 in which said reactionproduct is prepared by reacting tetrapropenyl succinic acid withunsymmetrical dimethyl hydrazine.

10. A gasoline composition according to claim 5 in which said reactionproduct is prepared by reacting tetrapropenyl succinic acid withhydrazine.

References Cited UNITED STATES PATENTS 2,638,450 5/1953 White et a1.44-7l 3,148,960 9/1964 Becker 4471 3,219,666 11/1965 Norman et a1.25251.5X

DANIEL E. WYMAN, Primary Examiner.

Y. H. SMITH, Assistant Examiner.

